Nick Clegg has said the coalition plans to reintroduce 'exit checks' to ensure that visitors who come to Britain for a limited period leave again.
He said that the previous Labour government abolished these.
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Wintry scenes across the UK this late in April have not been seen since the mid-1980s.
The Labour leader will also announce an inquiry into anti-semitism and other forms of racism to be chaired by Shami Chakrabarti.
A switch in the wind direction will mean the unseasonably bitterly cold air of the last few days finally gives way.